diff --git a/src/gasflux/reporting.py b/src/gasflux/reporting.py
index a5bc2be..23de789 100644
--- a/src/gasflux/reporting.py
+++ b/src/gasflux/reporting.py
@@ -27,13 +27,22 @@ def mass_balance_report(
     """Generate a mass balance report (plots disabled)."""
     template_path = Path(__file__).parent / "templates" / "mass_balance_template.html"
 
-    # Plots disabled -> use empty strings
+    # Convert figures to HTML strings
+    def _fig_to_html(fig) -> str:
+        """Safely convert a plotly figure to HTML string."""
+        if fig is None:
+            return ""
+        try:
+            return fig.to_html(full_html=False, include_plotlyjs=True)
+        except Exception:
+            return ""
+
     plot_htmls = {
-        "3D": "",
-        "krig": "",
-        "windrose": "",
-        "wind": "",
-        "background": "",
+        "3D": _fig_to_html(threed_fig),
+        "krig": _fig_to_html(krig_fig),
+        "windrose": _fig_to_html(windrose_fig),
+        "wind": _fig_to_html(wind_fig),
+        "background": _fig_to_html(background_fig),
     }
 
     summary_data = {